On most of these pages we've been talking about polymers whose backbone
chains are made mostly of carbon atoms, if not entirely of carbon atoms.
These we call organic polymers. But now we're going to leave
convention behind and talk about some polymers that don't have any carbon
atoms in the backbone chain. These are called, as if you couldn't guess,
inorganic polymers. Here's a menu if the inorganic polymers on
this page to help you navigate:

They really should be called polysiloxanes. The bond between
silicon and oxygen is very strong, but very flexible. So silicones can
stand high temperatures without decomposing, but they have very low glass transition temperatures. You've probably seen
rubber or caulking made of silicones somewhere
before.

It formed crystals that were so strong that
nothing could dissolve them. Burkhard tried to heat it, but it wouldn't
melt below 250oC, when it decomposed, without melting. That made
polydimethylsilane pretty much useless. He made it by reacting sodium metal with dichlorodimethylsilane like this:

This is important, because in the seventies, some scientists got the
notion that they were going to make small rings of silicon atoms. So
unwittingly did something similar to what Burkhard had done. They
reacted sodium metal with dichlorodimethyl silane, but they also added
some dichloromethylphenylsilane to the brew. And guess what happened!
I'll give you a hint: they didn't get the rings they wanted. What they
got was a copolymer, like this:

Maybe that polymer is more clearly drawn like this:

You see, those phenyl groups get in the way when the polymer tries to
crystallize, so it isn't as crystalline as polydimethylsilane. This
means it is soluble and can be processed and played with and studied.

So what are these good for? Polysilanes are interesting because they can
conduct electricity. Not as well as copper, mind you, but a lot better
than you'd expect for a polymer, and worth investigating. They're also very
heat resistant, almost up to 300 oC, but if you heat them a
lot higher you can make silicon carbide out of them, which is a useful
abrasive material.

First we take phosphorus pentachloride and react it with ammonium
chloride to get a chlorinated polymer. Then we treat it with an alcohol
sodium salt, and that gives us an ether-substituted polyphosphazene.